The present disclosure relates to a comparator unit, a display, and a method of driving the display.
Light emitting diode (LED) displays using LEDs as light-emission device has been actively developed. In an LED display, a light-emission section including a red LED serves as a red light-emitting sub-pixel, a light-emission section including a green LED serves as a green light-emitting sub-pixel, and a light-emission section including a blue LED serves as a blue light-emitting sub-pixel. The LED display displays a color image based on emission states of these three types of sub-pixels. For example, in a 40-inch-diagonal full-HD (High Definition) full color display, the number of pixels in a horizontal direction of a screen may be 1920, and the number of pixels in a vertical direction of the screen may be 1080. Therefore, in this case, the number of mounted LEDs is about six millions, which is 1920×1080×(the number of three types of LEDs, i.e. the red LEDs, the green LEDs, and the blue LEDs, which are necessary to configure one pixel).
In an organic electroluminescence display (hereinafter simply abbreviated to “organic EL display”) using an organic electroluminescence device (hereinafter simply abbreviated to “organic EL device”) as a light-emission section, a variable constant current driving method in which a light emission duty is fixed is widely used for a drive circuit that drives the light-emission section. Further, from the viewpoint of reducing light emission unevenness, a PWM-driven organic EL display is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2003-223136 (JP2003-223136A). In a method of driving an organic EL display disclosed in JP 2003-223136A, in a first period at the beginning of one frame period, an image signal voltage is written to each of all pixels, in a state in which light emission of a current-driven-type light-emission device in each of all the pixels is stopped. Further, in a second period following the first period in the one frame period, the current-driven-type light-emission devices of all the pixels are allowed to emit light simultaneously, within one or more light emission periods determined by the image signal voltage written to each of the pixels.